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Thread: Canon S90 purple fringing

  1. #1
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    Canon S90 purple fringing

    Hi,

    Has anyone got any tips for removing the purple fringing from photos taken with an S90? I have tried without success to remove it using the chromatic aberration tool in Lightroom, though it does reduce it slightly.

    Is this to be expected from a S90 or is there a fault?

    Here are some examples of the problem:
    (Straight from RAWs with no processing in LR)

    Canon S90 purple fringing
    ISO125 12.8mm F5 1/200

    Canon S90 purple fringing
    (enlargement from above)

    Canon S90 purple fringing
    ISO160 6mm F2.2 1/320 (yea I know it should have been stopped down!)

    cheers

  2. #2
    jiro's Avatar
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    Willie or Jiro is fine by me.

    Re: Canon S90 purple fringing

    Use the HSL adjustment options and lower down the values of the Aqua, Blue, Purple, and Magenta colors on the Saturation. On the luminance, lower only the values of the blue, purple, and magenta. Adjust the recovery value to +79, and clarity to +63. That should help lessen the effect of the color fringing.

    Canon S90 purple fringing

  3. #3
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    Re: Canon S90 purple fringing

    cheers for that. But what if I want some purple in the shot?

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    Re: Canon S90 purple fringing

    You would probably have to select that area and invert the selection so that area would be excluded. Or work with layers and masks so that the correction could be limited to a layer with a suitable mask.

  5. #5
    Black Pearl's Avatar
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    Re: Canon S90 purple fringing

    How big did you have to print it before you saw the fringing?

  6. #6
    John C's Avatar
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    Re: Canon S90 purple fringing

    The purple fringing is an artifact of the lens. Some lenses show it more than others and it typically appears most with high contrast backlit situations (i.e. branches against the sky, etc.). I have been using DxO Optics Pro as a RAW converter and it does an excellent job with chromatic aberration (and purple fringing). DxO uses corrections specific to your camera, lens, and settings to remove optical problems. After trying several other products, I like it the best. My older Sony F828 has a purple fringing problem similar to your Canon S90 and DxO did a really good job of clearing it up. Its other corrections are also very good. It is supposed to work as a front-end to Lightroom and it is available on a trial basis. You might wan to check it out.

    The link below has a description of the problem and how it is corrected.
    http://www.dxo.com/en/photo/dxo_opti...ons/aberration

  7. #7
    Moderator Dave Humphries's Avatar
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    Re: Canon S90 purple fringing

    Hi Rob,

    I'd certainly suggest following JohnC's idea for an automatic fix.

    My method for dealing with CA is to wipe a strong desaturaion brush over the offending branches, this brush is usually the third option (looking like a sponge) under the dodge and burn icon in something like PS Elements or PS CS3/4/5 (if you have it). It allows you to only put it where needed and since you generally don't need to be too accurate, with good use of image zoom and brush size, it can be quite quick to do.

    I don't get much with my current DSLR lenses, but it is often a problem with P&S and bridge camera lenses, my Fuji S6500 was susceptible to it given 'the wrong conditions' such as you have here. Over exposure does make it worse, so do "stop it down" when you know you should

    Welcome to the CiC forums from ....

  8. #8
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    Re: Canon S90 purple fringing

    Thanks for the good advice, will try those techniques.

    I mainly use LR and just getting to grips with CS5, knew there must be a good method hidden there somewhere!!

    I dont get see this with my DSLR either but sometimes weight is an issue when I'm climbing!!

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